Ion Mobility Spectrometry

What is IMS (Ion Mobility Spectrometry)?

Ion Mobility Spectrometry is an analytical technology to separately detect gaseous compounds in a mixture of analytes. The separation is based on the specific drift times, that ionized compounds need to pass a fixed distance (drift tube) in a defined electric field. The drift times of each substance is determined by it’s ion’s mass and geometric structure as slowing collisions with the drift gas tube are more frequent for sterically demanding structures. Therefore IMS can even differentiate between isobaric molecules. For detection, the resulting ion current is measured by an electrometer as a function of time.

IMS (ion mobility spectrometry) is an analytical technique ideal for the analysis of gaseous samples and the headspace of liquid samples.

IMS is extremely fast and sensitive and is the ideal technique when fast results are needed, when very low levels of compounds are seeked or when there is an interest in taking the analysis to the point of need rather than taking the samples to the laboratory.

IMS and other techniques

Would you like to understand whether IMS is the right choice for your lab or application? This table may help you:

TD/GC/MSD

PTR-TOF-MS

SIFT-MS

MCC/IMS

Deployment

Laboratory

Laboratory

Laboratory

Lab & Point-of-Care

Mass range

1050 amu

20 – 180 amu

< 300 Da

< 1000 Da

Ions

positive

positive

positive

positive, negative

Detection limit

ppbv-ppmv

pptv

ppbv

pptv-ppmv

Gas consumption

Helium

Helium

Helium

Air

Vacuum pump needed

yes

yes

yes

no

Measurement time

60 – 120 min

30 min

30 min

10 min

Weight

96 kg

170 kg

212 kg

18 kg

Dimensions (cm x cm x cm)

88 x 56 x 50

56 x 130 x 78

90 x 72 x 88

45 x 35 x 28

Personnel needed for operation

Scientist

Scientist

Scientist

Technician

GC-IMS vs GC-MS

While IMS can be complimentary with many analytical techniques, it can often be seen as an alternative to GC-MS. So, how do they compare?